The present invention relates to the field of downhole oil, gas, and/or geothermal exploration and more particularly to the field of drill bits for aiding such exploration and drilling.
Drill bits use rotary energy provided by the tool string to cut through downhole formations, thus advancing the tool string further into the ground. To use drilling time effectively, sensors have been placed in the drill string, usually in the tool string, to assist the operator in making drilling decisions. In the patent prior art, sensors have been disclosed in drill bits.
For example, U.S. Pat. No. 6,150,822 to Hong, et al discloses a microwave frequency range sensor (antenna or wave guide) disposed in the face of a diamond or PDC drill bit configured to minimize invasion of drilling fluid into the formation ahead of the bit. The sensor is connected to an instrument disposed in a sub interposed in the drill stem for generating and measuring the alteration of microwave energy.
U.S. Pat. No. 6,814,162 to Moran, et al discloses a drill bit, comprising a bit body, a sensor disposed in the bit body, a single journal removably mounted to the bit body, and a roller cone rotatably mounted to the single journal. The drill bit may also comprise a short-hop telemetry transmission device adapted to transmit data from the sensor to a measurement-while-drilling device located above the drill bit on the drill string.
U.S. Pat. No. 6,913,095 to Krueger discloses a closed-loop drilling system utilizes a bottom hole assembly (“BHA”) having a steering assembly having a rotating member and a non-rotating sleeve disposed thereon. The sleeve has a plurality of expandable force application members that engage a borehole wall. A power source and associated electronics for energizing the force application members are located outside of the non-rotating sleeve.